$$\begin{split} {s_{{\rm{mov,}}n}}\left( t \right) =& \exp \left\{ { - {\rm{j}}\frac{{4\pi \left( {{f_{\rm{r}}} +
{f_{\rm{c}}}} \right)}}{{\rm{c}}}{R_0}} \right\} \exp \left\{ { - {\rm{j}}\frac{{4\pi \left( {{f_{\rm{r}}} +
{f_{\rm{c}}}} \right)}}{{\rm{c}}} \left( {{u_{\rm{r}}} - {v_{{\rm{rv}}}}\sin \left( {{\theta _{{\rm{sq}}}}} \right)}
\right) \left( {t - \frac{{\Delta {x_n}}}{{2{v_{{\rm{rv}}}}}}} \right)} \right\} \\ & \cdot \exp \left\{ { -
{\rm{j}}\frac{{2\pi \left( {{f_{\rm{r}}} + {f_{\rm{c}}}} \right)}}{{{\rm{c}}}}
\frac{{v_{{\rm{rv}}}^2{{\cos }^2}\left( {{\theta _{{\rm{sq}}}}} \right)}}{{{R_0}}}{{\left( {t - \frac{{\Delta
{x_n}}}{{2{v_{{\rm{rv}}}}}}} \right)}^2}} \right\} \\ & \cdot \exp \left\{ { - {\rm{j}}\frac{{2\pi \left( {{f_{\rm{r}}}
+ {f_{\rm{c}}}} \right)}}{{\rm{c}}} \frac{{v_{{\rm{rv}}}^3\sin \left( {{\theta _{{\rm{sq}}}}}
\right){{\cos }^2}\left( {{\theta _{{\rm{sq}}}}} \right)}}{{R_0^2}}{{\left( {t - \frac{{\Delta
{x_n}}}{{2{v_{{\rm{rv}}}}}}} \right)}^3}} \right\} \\ & \cdot \exp \left\{ { - {\rm{j}}\frac{{2\pi \left( {{f_{\rm{r}}}
+ {f_{\rm{c}}}} \right)}}{{\rm{c}}} \left( {\frac{{{u_{\rm{r}}}\Delta {x_n}}}{{{v_{{\rm{rv}}}}}} +
\frac{{{{\cos }^2}\left( {{\theta _{{\rm{sq}}}}} \right)\Delta x_n^2}}{{4{R_0}}}} \right)} \right\} \\ =&
{s_{{\rm{mov}}}}\left( {t - \frac{{\Delta {x_n}}}{{2{v_{{\rm{rv}}}}}}} \right) \cdot \exp \left\{ { -
{\rm{j}}\frac{{2\pi \left( {{f_{\rm{r}}} + {f_{\rm{c}}}} \right)}}{{\rm{c}}} \left( {\frac{{{{\cos }^2}\left( {{\theta
_{{\rm{sq}}}}} \right)\Delta x_n^2}}{{4{R_0}}} + \frac{{{u_{\rm{r}}}\Delta {x_n}}}{{{v_{{\rm{rv}}}}}}}
\right)} \right\} \\ \end{split} $$